Mammography is key to early detection of breast cancers because it can reveal changes in the breast up to two years before they can be felt through the skin. It is also used to evaluate women who show symptoms of a breast disease, such as a lump, nipple discharge, breast pain, dimpling of the skin on the breast, or retraction of the nipple. The use of screening mammography increases the detection of all types of breast cancer, including small abnormal tissue growths confined to the milk ducts in the breast, called ductal carcinoma in situ (DCIS). The earlier cancer is found, the more treatment options a woman has and the more likely a cure.

A mammogram involves exposing the breasts to a small dose of radiation (X-rays) to produce pictures of the inner breast. A mammography unit is a rectangular box that houses X-ray technology. Attached to the unit is a device that holds and compresses the breast and positions it so images can be obtained at different angles. Once it is carefully aimed at the breast, the unit produces a small burst of radiation that passes through the body, recording an image on film or a special digital image recording plate.

Until recently, X-ray images were maintained as hard film copy. Today, most images are digital files that are stored electronically, a system called digital mammography in which X-ray film is replaced by detectors that convert X-rays into electrical signals. These stored images are easily accessible and can be compared to new X-ray images to show changes in breast tissue. This digital information can be manipulated for further evaluation more easily than information stored on film. Except for the difference in how the image is recorded and stored, there is no other difference between the two types of mammography.

During your exam you will be asked to undress from the waist up and will be given a gown to wear. Depending on the type of equipment used, you will either sit or stand. A radiologic technologist will position your breast in the mammography unit. He or she will gradually compress your breast with a compression paddle or compressor (often made of clear Plexiglas or other plastic). You will feel pressure on your breast as it is squeezed. Some women with sensitive breasts may experience discomfort. If this is the case, schedule the procedure for the time of month when your breasts are least tender. Be sure to inform the technologist if you feel increasing pain as compression is increased.

The X-ray pictures are taken from several angles. The routine views are a top-to-bottom view and an oblique side view. You may be asked to hold your breath as each picture is taken. You will be asked to change positions between images. The process will be repeated for the other breast. When the examination is complete, you will be asked to wait until the radiologist confirms that all the necessary images have been obtained. The entire process should take about 30 minutes.

After your procedure, a radiologist will analyze the images and send a report to your primary care or referring physician, who will discuss the results with you. You will also be notified of the results by the mammography facility. Ask when your results will be available; do not assume the results are normal if you do not hear from your doctor or the mammography facility.

Sometimes you will be asked to come back for additional testing. This is not always a cause for concern. Rather, the doctor may simply need to recheck an area that could not be clearly seen on the first test.

Do not schedule your mammogram for the week before your period if your breasts are usually tender during this time. The best time for a mammogram is one week following your period.

Tell your health care provider and the radiologist or technician if you are pregnant or breastfeeding.

Do not wear deodorant, perfume, powders or ointments under your arms or on your breasts on the day of the mammogram. These substances may obscure the images and can appear on the mammogram as calcium spots.

Remove all jewelry from your neck and chest area.

Describe any breast symptoms or problems to the technologist performing the exam.